High disease inoculum levels could prompt need for seed treatment

Septoria tritici and rust pressures encountered this season will mean more inoculum around at drilling time warns Mark Hemmant, technical manager at Agrovista.

“A good seed treatment will be an important insurance policy, especially when subsequent T0 sprays are missed, as many were this spring.”

Results from Agrovista trials have helped to identify which seed treatment is best suited to which situation and also the interaction between the extent of disease control from a seed treatment either with, or in the absence of, early foliar treatments, Mr Hemmant says.

In trials, the fluquinconazole-based seed treatment, Epona, was compared with a standard single purpose dressing (SPD) on a first wheat crop and across a range of subsequent foliar fungicide treatments applied where Septoria tritici was the main pathogen. 
“In septoria-susceptible varieties grown as first wheats, we were seeing yield bonuses of around 0.5-0.6 t/ha using Epona. We have also seen good greening and vigour effects. Such a seed treatment can have a short-term effect on delaying septoria development.

The delay in septoria onset could be useful this autumn due to the large amounts of inoculum that will be about from this year’s crop, he notes.

Using a foliar disease-acting seed treatment to deal with early septoria could, in Mr Hemmant’s view:

• Provide more flexibility in the timing of the T1 application
• Reduce pressure on the spring sprays
• Increase yield

But care over which foliar disease-acting treatment to use is essential, AICC agronomist Peter Cowlrick says. Speaking to Crops magazine last month he explained that the widespread use of fluquinconazole (and prothioconazole) should be avoided for resistance management, recommending its use only for varieties such as Cordiale where septoria can take an early hold in the spring.

The use of Baytan Flowable is an alternative option to slow crop development on fertile sites, especially lodging-prone and yellow rust-susceptible varieties such as Robigus, he explains.

Baytan, Epona, Jockey and Galmano all have label claims for foliar disease control in wheat.